Subject: ARP, MCAP, signature

From: "Hattig, Myron" <[email-masked]>
Date: Mon, 21 Dec 1998 12:09:46 -0800

ARP -----------------------------

I propose we adopt the ARP format in the draft

http://www.ietf.org/internet-drafts/draft-johansson-ip1394-asynch-streams-00
.txt

It is on page 9 in figure 5.

MCAP -----------------------------

For MCAP, I propose we replace the following header
                     1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|             length            |           reserved            |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|     bus_ID        |   phy_ID  |    reserved   |     opcode    |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
With
                     1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|             length            |    reserved   |     opcode    |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Previously, the purpose of the bus Id was to ensure MCAP
packets from another bus would not have meaning on the local bus.
The phy ID was used to resolve contention among multiple owners of
the a channel mapping. The bus ID is now part of the GASP header,
so now the algorithm related to the bus ID only changes to look at
the bus ID in the GASP header. The algorithm related to the phy
ID also only changes to examine the phy ID in the GASP header.

Signature -----------------------------

For the signature, I propose to change the definition of
the signature field. The definition is:
-------------
> signature: The sender shall set this field to the most significant
> 16-bits of its own NODE_IDS register.
-------------
A follow-on note states:
-------------
> NOTE: The use of signature for any purpose other than link fragment
> reassembly is fraught with error and is strongly discouraged.
-------------
We should define the signature as:
> signature: A 16 bit value unique among all nodes on the 1394 bus. In
> single 1394 bus networks, the signature is the most significant
> 16-bits of the sender's NODE_ID register. In multiple-bus 1394 networks,
> the use of the sender's node ID should be re-examined to maintain
> the requirement that the signature values be unique among all nodes
> connected in the 1394 network. Because the signature may not always
> be the sender's node ID, using the signature for any purpose other than
> link fragment reassembly is fraught with error and is strongly
discouraged.

-myron

---

From: Kenji Fujisawa <[email-masked]>
Date: Thu, 24 Dec 1998 10:56:25 +0900

>> link fragment reassembly is fraught with error and is strongly

I can live with this, but I prefer to change this 16-bit field as
a 'reserved'.

Kenji Fujisawa